A thermocouple provides an output of between 4 and 20 mA, corresponding linearly with temperature. The thermocouple is first placed in boiling water at 1.0018 atm, and provides an output of 12.32 mA. The thermocouple is then placed in boiling toluene at the same pressure and provides an output of 12.59 mA.
A. Derive a formula that converts the output from the instrument into a reading in degrees C.
B. Convert the formula to provide an answer in degrees F.
C. Why do you think the thermocouple has an output range of 4 to 20 mA instead of 0 to 16 mA?
D. What do you think are the operating limits of the instrument? Report your answer in degrees F.